[pct-l] Bleeding off Lithium Batteries

[Bastian Schlagowsky]

I used Lithium batteries in my Garmin geko and had no problems altough I replaced them with new ones every three weeks...

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> -----Ursprüngliche Nachricht-----
> Von: <stewjohns at comcast.net>
> Gesendet: 13.04.08 17:51:28
> An: pct-l at backcountry.net (PCT-L list)
> Betreff: [pct-l] Bleeding off Lithium Batteries


> 
> I bought some new Lithium batteries for my Garmin GPS the other day, and when I put them in,
> and turned on the unit, it came on for a few seconds and then the display faded out and the unit
> turned off.  The problem is that Lithium batteries come out of the box with a voltage of 1.8v, while
> the equivalent alkaline battery has an out of the box voltage of 1.6v.  The extra voltage of the 
> Lithium, triggers the over voltage circuit in the GPS, and it shuts it off.  The solution is to bleed off some of this voltage by running it through some other device for a bit.  
> 
> Being a curious electronic technician, I wanted to quantify this a bit and find out how much you 
> need to bleed off before you can use them in the GPS.  I pulled out my fluke multi-meter and measured the out of the box starting voltage of both alkaline and lithium batteries.
> Alkaline = 1.6V
> Lithium = 1.8 V
> 
> I then installed the New Lithium batteries in the GPS to verify that they would not work.
> Then after confirming that they wouldn't, I installed them in a mini-mag flashlight.  My plan was
> to run the flashlight for 1 minute, measure the voltage of the battery, and than install them back in
> the GPS to see if they worked.  I intended to repeat this at 1 minute intervals until I could get
> them to work in the GPS.  My experiment lasted only 1 minute of data, as after 1 minute in 
> the flashlight, the Lithiums worked fine.  Measured voltage after the 1 minute bleed off---1.72V.
> It doesn't take much bleed off to get them to work.
> 
>  If you are a GPS user, and want to take
> advantage of the extra life that Lithium batteries provide, I would suggest you test your spares
> before you head out to the trail-head, and bleed them off a little if necessary.  I suppose you could
> rig something in the field if you had to, but why not be prepared ahead of time.
> 
> The GPS unit tested was a Garmin map 60CSX.  The Batteries tested were Energizer Lithium AA,
> and Duracell alkaline AA.
> 
> Doc Holiday
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-- 
Bastian Schlagowsky
+49 (176) 20646551
Bastian.Schlagowsky at web.de